/* ========================================================================
 * Copyright (c) 2005-2025 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * The complete license agreement can be found here:
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 * ======================================================================*/

using System;
using System.IO;
using Opc.Ua.Bindings;

namespace Opc.Ua.Fuzzing
{
    public static partial class FuzzableCode
    {
        public static ServiceMessageContext MessageContext { get; set; }

        /// <summary>
        /// Print information about the fuzzer target.
        /// </summary>
        public static void FuzzInfo()
        {
            Console.WriteLine("OPC UA Core Encoder Fuzzer for afl-fuzz and libfuzzer.");
            Console.WriteLine("Fuzzing targets for various aspects of the Binary, Json and Xml encoders.");
        }

        /// <summary>
        /// Prepare a seekable memory stream from the input stream.
        /// </summary>
        private static MemoryStream PrepareArraySegmentStream(Stream stream)
        {
            const int segmentSize = 0x40;

            // afl-fuzz uses a non seekable stream, causing false positives
            // use ArraySegmentStream in combination with fuzz target...
            MemoryStream memoryStream;
            using (var binaryStream = new BinaryReader(stream))
            {
                var bufferCollection = new BufferCollection();
                byte[] buffer;
                do
                {
                    buffer = binaryStream.ReadBytes(segmentSize);
                    bufferCollection.Add(new ArraySegment<byte>(buffer));
                } while (buffer.Length == segmentSize);
                memoryStream = new ArraySegmentStream(bufferCollection);
            }

            return memoryStream;
        }
    }
}
